Pinewood derby- lane brain and not pinewwod??

[Karen_216]

Hi folks,

Just got done another pinewood derby and it seems like every year something else happens. (need to add ot the rules book!!)

This year a car was entered that looked to be some other type of wood.(don't know if it was just , there was a question about it that occured during the races after check-ins).

Officials noticed when handling the car and turned it over and there was some discussion that is looked like another type of darker wood than pine. Not extremely darker like walnut but maybe chestnut a Dad thought(and maybe the grain as well being darker than pine? but it had been cleared and was half way through so we let it go on.

You know how hectic it can be at check in and we were checking wheels and weighing , checking height, and weight, length and obvious things like clearly not wood material -- guess we need to add an area to check the type of wood as well now!! The oficials actually thought it may be medal at first as it seemd "heavier'- maybe because of design?? It definately was not over wieght...

Anyway this car was in a dead heat with another car when it looked like the lane brain was not registering correctly (this was den heats not pack finals)-- another car seemed clearly to be slightly winning and was coming up 2nd. Several adults even said so- those that had no stake in the race. Other car was very shiny so we thought maybe it wasn't registering so started doing the finish by sight. Of WE told him sure we can -- we're the officials and rules state we can make decisions like that.(we didn't mention that maybe car was not legal anyway)

Anyone else have problems like this??

Lane brain does not register at finish correctly (there were no notches in either) or have questionable materials??

We have a separate race and everything for other mateials and wheels to be used.

We did disqualify a car during a race one year because wheels were not correct. But sheesh--- use another type of wood?? I'm not even sure that was they case- if he fired the car would that make it darker?? I'm not a wood expert so I gave the call to the pinewood chair on it.

[gcnphkr]

Most finish lines I've seen are simple electric eyes. Just having a shiny car would not affect it. Possibly the lights were out of line, but that is also unlikely. There could have been a circuit issue. In any case if it seemed to only affect this car then it is likely there was no actual problem and you should have let it win. If you judged that car different from any other car then you should go back and appologize to the boy.

 

I am a purist. I believe that any rule beyond those that come in the box are bogus.

There is no rule that the scout must use the wood block that came with the kit. If they want to use pine, ironwood or balsa it is all legal. There is no rule that a wheel cannot be sanded, shaved, lathed or filled with lead. There is no rule that the axles must use the original grooves.

 

BTW. The only reason that there is any need for other rules is because father's can't let their sons just have fun building the car they want. So if you want a valid additional rule: The scout must pledge, "On his honor" that he built the car without Dad ever touching the car with anything other than his fingers.

[DeanRx]

I will have to respectfully disagree w/ Jet on this one. I DO agree that too many times it becomes a 'dad' built car with little input from the scout.

 

However, the goal is for the adult and scout to spend time together, the scout to LEARN some things about drag, friction, woodworking, painting, etc... and to have fun with it.

 

If the 'adult' is only allowed to touch the car w/ their hands, then very few (if any) of the Tiger's and Wolves cars would even get across the finish line. Not much fun for the boys.

 

OK - off the soapbox and on to the tech questions...

 

1) Finish on the car should not have influenced the timing lights. One way to tell would be to call a "time-out" and test out both lanes with non-competing cars to make sure both lane lights were functioning correctly. If they are and the "suspect" car won, then let it win. If you are going to over-ride your electronic timers, then you should be video taping the finish line and be able to play-back in a frame-by-frame method. Otherwise, why bother setting up an electric timing system? Most of our pack's cars ran in the area of 3.7 secs on a 50ft track. That translates to just under 10 mph (actual average speed) for most cars. That doesn't seem like much until you're trying to watch 4 cars all under 7 inches long moving that fast. Hard to do with the naked eye.

 

2) Unless your rules sheet specifically states that the car must be constructed out of the block in the kit, then you really don't need to worry about the wood.

 

IF? they baked it prior to building (which some people do - and I/we have done to prevent warping due to moisture loss) - then YES the pinewood will take on a slightly darker tone. The hotter and longer its baked the darker it will likely be.

 

Bottom line - machining of axles / wheels, and weight are the TWO largest factors in the speed of a car. Camber (the alignment / 'wiggle' in the wheels) is the 3rd factor. Aerodynamics runs a very distant 4th in determining speed.

 

If the car meets size specs, is within weight, and doesn't have CNC machined or automated-lathe wheels and axles, it likely doesn't have an unfair advantage. Wheel running surfaces should not be rounded, but can be sanded to remove burs. Tread width should not be thinned or reduced in any manner. (Our pack and council rules state that the little nubs on the outer wall circumfrence of the wheel must still be visible, or else the wheel has been 'shaped' too much)

 

Type of wood used would have very little to no bearing on performance and should not be used as a reason to suspect or DQ a car in my book.

 

DeanRx

[Gunny2862]

Unless you are going to DQ due to it not being the same Wood supplied and that rule is clearly stated, not just a vague expectation then, I would have an issue here.

 

As long as it is the correct dimensions and doesn't weigh in heavy, both valid reasons to DQ, the what does it matter what it's made of? Unless you have the material the car is to be built of, clearly stated in your rules.

[ElyriaLeader]

I still like the carbon - fiber car that was entered last year....dad swore up and down that his son made it!, no one wanted to believe him, but the son was able to explain the layup process and the dad did say that he had made the mold the son used to do the layup in,interesting...led us to add the rule that you must use the BSA supplied kit parts.

[ManyHats]

Our pack pays for each scouts car. I don't think it's too much to ask that they use the kit entirely.

Last year we had to DQ a car for rubber tires. Luckily dad's car for the open class was identical except it had BSA tires, so they just switched them.

[Karen_216]

We have rules of;

Must be BSA wheels and axles, Wheels can't be altered- only to smooth off the rough sport. we also have a lenght, heigth, width and wheelbase limit. you don't have to use the predrilled holes. Most of these are so they go freely donwn track and don't interfere with other cars.

also may be hollowed out and buitl up to weight by adding wood or metal only.

we give out the car kits for free to each scout.

I think our rules are pretty standard. Maybe some specific to the track race for clearance reasons.

We have a separate "open class" race. Basically car must not interfere with others, fit on track and under timer and limited to 5oz. we've had some pretty cool entries in this one.

[Crew21_Adv]

Karen_216,

 

I dont see any problem. The car was within weight and dimension standards.

 

Did it pass registration?

 

If the wood made it heavier, yes, that would be an issue. But it was weighed within standards, correct?

 

Regarding, questioning methods to enter cars into a Pinewood Derby....

The best I ever heard was a hollowed out car, which had a liquid test tube inserted into the length car. The fluid would gravitate towards the front giving an additional pulling weighted start, but on the straight away the fluid in the test tube would level out maintaining a consistent cruising speed. I would like to have seen it in race, the mental image seems like it would win.

 

Back to this shiny car, possibly of another wood, Maybe the other parents/den leaders were just jealous?

 

Scouting Forever and Venture On!

Crew21 Adv

 

[gpraceman2]

Having a shiny car may very well cause a problem with a finish line sensor. This is especially true if the track surface is reflective (metal or even a glossy finish).

If the bottom of the car is shiny, then light can bounce off of the track surface and underside of the car to cause problems with the sensor detecting the car passing over. There is at least one timer manufacturer that warns of this issue.

 

One countermeasure is to paint a flat black stripe across the finish line area to reduce the chance of light bouncing off of the track. Another countermeasure is to recess the track sensors a bit more into the track so they are peering through a short tunnel up at the light source.

[DenZero]

The Lane Brain uses photocells in holes in the track with a light bar above. A reflective car should not affect it. Ours will trigger falsely if the photocells are not straight and level, and if the light bar is not straight and square above the track at an optimal height. It works best with the tubular bulbs. I suspect that it would be easily confused by strong ambient light.

[gpraceman2]

DenZero = "I suspect that it would be easily confused by strong ambient light."

 

That was my concern. Not the light from the Lane Brain unit itself.

 

[shortridge]

Wow. Things sure have changed since I was a Cub in the '80s. Then the biggest worry was about weights.

 

As a den chief in the '90s, I was a finish-line judge, one of two people stationed at the end of the track. No electronic systems, no concerns about shiny cars. And no one then had even heard of baking a car. (Did I read that right?)

 

I always liked the Space Derby a lot more than the PWD. The balsa shell was much easier for a lone Webelos to shape and sculpt than a block of wood - so no need for a parent to get involved. And the Raingutter Regatta I still think is the ultimate fun event, the epitome of KISMIF. Even the tiniest Wolf can win if he has a good set of lungs.

 

Seems like the more rules you have, the more of a challenge it is to the fathers to find loopholes and ways to get around them.

[Vicki]

I'm with you, Shortridge. Always did love the simplicity and fun of the Regatta. Also less pressure, less politics, less cost...

 

Vicki

[packsaddle]

this one was also popular

[gpraceman2]

packsaddle,

 

I'm not sure why you are bumping a bunch of old Pinewood Derby threads.